They even go a step further by handcuffing a 19-year-old girl who turned herself in at the police station. There was absolutely no need to do so as she was not resisting arrest.
But when opposition politicians and others deemed linked to the opposition leaders are disparaged, the police turn a blind eye.
The decision by the people to turn up at Dataran Merdeka to hold the government to its promises of electoral reforms started the ball rolling.
Some government leaders accused the opposition of orchestrating the event.
The government was unhappy to say the least and decided not to hold the yearly countdown event to usher in Merdeka.
And the police were more than happy to go to the carpet and outlandishly mobilise a team to nab anyone they deemed had acted in an inappropriate manner.
Two youths who displayed the Sang Saka Malaya flag were also detained. They have clearly denied their act was to call for a replacement of the national flag.
But this was construed as a covert attempt by,who else but the opposition, to change the Jalur Gemilang and the police are still hunting down others. So far 11 young people have surrendered.
But what is jarring is the complacency adopted by the force when it comes to investigating matters concerning opposition leaders and members of the civil society.
Firstly, high-ranking police officers would ramble incoherent statements to try and protect the ruling elite.
Then they would throw their "intellectual" weight behind the perpetrators by making excuses for them. And lastly the perpetrators would go free.
We have seen this happening repeatedly in the country.
The police did not act with the same fervor when DAP sec-gen Lim Guan Eng's posters were burnt, a mock funeral was held in front of his home and cakes, in the form of faeces, were delivered to him.
Bersih chairperson AmbigaSreenevasan's posters were also burnt while PAS spiritual guru Nik Abdul Aziz and PAS president Abdul HadiAwang's photos in a banner were urinated on.
Retired army officers flexed their posterior muscles outside Ambiga's house and traders set-up shops as a sign of protest against the rally calling for free and fair elections in July.
In a response, the police said the musclemen and burger flippers were in a public space.
And another case, among the many others, is the cow head demonstration in August 2009 which was brought about by the opposition-led Selangor government's decision to relocate a Hindu temple to a Muslim majority area.
Cows are considered sacred by Hindus.
The protesters stomped and spat on the cow head and said there would be blood if the temple relocation goes through. This was recorded on video.
But although the protest threatened the racial fabric of the society, Home Minister Hishammuddin Hussein defended the protesters, saying they just wanted their voices to be heard.
Once again, the police have proven that they are the bully-boys who would not hesitate to act on the instruction of their Umno bosses. And in the process, they have only disgraced themselves even further.
CHARLES SANTIAGO is Member of Parliament for Klang.